revlog: increase I/O bound to 4x the amount of data consumed
This doesn't affect normal clones since they'd be bound by the CPU bound below
anyway -- it does, however, improve generaldelta clones significantly.
This also results in better deltaing for generaldelta clones -- in generaldelta
clones, we calculate deltas with respect to the closest base if it has a higher
revision number than either parent. If the base is on a significantly different
branch, this can result in pointlessly massive deltas. This reduces the number
of bases and hence the number of bad deltas.
Empirically, for a highly branchy repository, this resulted in an improvement
of around 15% to manifest size.
from mercurial import demandimport
demandimport.enable()
import re
rsub = re.sub
def f(obj):
l = repr(obj)
l = rsub("0x[0-9a-fA-F]+", "0x?", l)
l = rsub("from '.*'", "from '?'", l)
l = rsub("'<[a-z]*>'", "'<whatever>'", l)
return l
import os
print "os =", f(os)
print "os.system =", f(os.system)
print "os =", f(os)
from mercurial import util
print "util =", f(util)
print "util.system =", f(util.system)
print "util =", f(util)
print "util.system =", f(util.system)
import re as fred
print "fred =", f(fred)
import sys as re
print "re =", f(re)
print "fred =", f(fred)
print "fred.sub =", f(fred.sub)
print "fred =", f(fred)
print "re =", f(re)
print "re.stderr =", f(re.stderr)
print "re =", f(re)
demandimport.disable()
os.environ['HGDEMANDIMPORT'] = 'disable'
demandimport.enable()
from mercurial import node
print "node =", f(node)